also, this kind of tautology prevents you from being able to have insight or perceive new aspects of the world. "art is what they put in galleries" is directly limiting you to your own cultural preconceptions and refusing to imagine them being totally wrong. If you have this attitude, you can't say stuff like 'wild bee hives/termite mounds are art because they have secret aspects that are not for practical use' (I just made that up) because they aren't in galleries or made by artists
the sociological posture to interesting philosophical questions is so damn annoying. "art is what they put in art galleries, math is what mathematicians do". an active turning-away from an interesting question, towards a boring non-answer. people should throw tomatoes at guys who say this